Drug interactions of the main antituberculosis drugs
| Drug | Level increased by | Level decreased by | Increases level of | Decreases level of |
|---|---|---|---|---|
| Isoniazid | Prednisolone | — | Phenytoin | Enflurane |
| Ethionamide | Carbamezepine | Azoles | ||
| Warfarin | ||||
| Diazepam | ||||
| Pyrazinamide | — | — | Probenecid | — |
| Ethambutol | — | Al(OH)3 | — | — |
| Rifampicin | — | PAS | — | Warfarin |
| Ketoconazole | Other azoles | |||
| Sulphonylureas | ||||
| Oral contraceptives | ||||
| Glucocorticoids | ||||
| Phenytoin | ||||
| Diazepam | ||||
| Theophyllines | ||||
| Vitamin D | ||||
| Digitoxin | ||||
| Methadone | ||||
| Protease inhibitors | ||||
| Cyclosporin |
Modified from Winstanley PA, in Clinical tuberculosis (Davies PDO, ed), 1994, Chapman Hall, London with permission.